Method for producing low bromine number fraction

Abstract

A fraction of low bromine number mainly containing a styrenic compound/aromatic compound adduct can be attained, by feeding reaction materials of a styrenic compound and an aromatic compound to a fixed-bed flow reactor packed with a solid acid catalyst in a liquid phase at a temperature in the range of 40 to 350° C. to form a styrenic compound/aromatic compound adduct, in which (1) the feed of reaction materials is stopped when the bromine number of the above fraction is increased up to a predetermined value, (2) a saturated aromatic hydrocarbon having a mean value of the proportion of aromatic ring carbons in a molecule of 55% or more is fed to the reactor in a liquid phase at a temperature higher by 5 to 150° C. than that of the reaction mixture just before the above stopping, and (3) the feed of reaction materials is then restarted to obtain the fraction.

What is claimed is:  
     
       1. A method for producing a fraction of low bromine number mainly containing a styrenic compound/aromatic compound adduct, by feeding reaction materials of a styrenic compound and an aromatic compound having at least one hydrogen atom directly connected to the carbon atom of aromatic ring, to a fixed-bed flow reactor packed with a solid acid catalyst in a liquid phase at a temperature in the range of 40 to 350° C. to form a styrenic compound/aromatic compound adduct and obtaining a fraction mainly containing said adduct by distillation, wherein 
       the feed of reaction materials to said reactor is stopped before the bromine number of said fraction increases up to 3 grams per 100 grams,  
       after that, in place of the feed of said reaction materials, a saturated aromatic hydrocarbon having a mean value of the proportion of aromatic ring carbons relative to total carbons in a molecule of 55% or more is fed to said reactor in a liquid phase at a temperature higher by 5 to 150° C. than that of the reaction mixture just before the above stopping of feed of reaction materials, and  
       then the feed of reaction materials is restarted to carry out the foregoing reaction so as to obtain a fraction of low bromine number.  
     
     
       2. A method of producing a low bromine number fraction as claimed in claim  1 , wherein said aromatic compound is benzene, toluene, xylene, ethylbenzene, cumene or a mixture of them. 
     
     
       3. A method of producing a low bromine number fraction as claimed in claim  1 , wherein said styrenic compound is styrene, α-methylstyrene or p-methyl-styrene. 
     
     
       4. A method of producing a low bromine number fraction as claimed in claim  2  wherein said styrenic compound is styrene, α-methylstyrene or p-methylstyrene. 
     
     
       5. A method for producing a low bromine number fraction as claimed in claim  1 , wherein the bromine number of said fraction is 0.1 gram per 100 grams or less.